Modern integrated circuits (or "chips") pass internal signals through layers of metallized strips that may be three or four levels deep. Referring to FIG. 1, depicted are three levels of metallized strips used to interconnect three structures or components, 100, 102, and 104. The top level comprises metallized strip 110 which is vertically coupled to structure 100 through conductor 120. In addition, metallized strip 110 is coupled to structure 104 through conductor 136.
The second level comprises metallized strip 112, coupled to structures 100, 102, and 104 through conductors 122, 128, and 134, respectively. The lowest level comprises two metallized strips 114 and 116. Metallized strip 114 is coupled to structures 100 and structures 102 through conductors 124 and 126, respectively, and metallized strip 116 is coupled to structures 102 and 104 through conductors 130 and 132, respectively.
The conductors and layers of metallized strips allow for chip structures to send signals to each other. For example, structure 100 sends a signal to structure 104 through conductor 120, metallized strip 110, and conductor 136. Structure 104 sends a signal to structure 102 through conductor 120, metallized strip 116, and conductor 130. In FIG. 1, the interconnections shown allow only one bit signals to be passed. To enable the communication of multiple bit data from structure to structure, on the other hand, a parallel series of conductors and metallized strips is conventionally employed, complicating the interconnection design.
As the number of structures increase, the number of interconnections increases exponentially. In this case, the metallized strips and conductors must snake through more levels of routing, complicating the design and manufacture of interconnections between structures.
Metallization technology has not advanced in terms of geometry reduction at the same rate as process technology. Another difficulty in reducing the geometry of interconnections is that the resistance of a conductor is inversely proportional to the cross-sectional area of the conductor. Thus, reducing the cross-sectional area of a conductor or metallized strip increases the resistance and hence power consumption of the chip.
Consequently, interconnection between structures of an integrated circuit continues to be problematic in chip design. In this case, it is desirable to reduce the number of separate metallized strips, the number of interconnection levels, and the amount of snaking throughout an integrated circuit.